The Berlin Pollution Control Facility started operating in August of 1979. The facility is designed to treat an average flow of 2.64 million gallons per day of wastewater and produce an effluent that will enhance the waters of the Androscoggin River. It is a Grade III secondary treatment, conventional activated sludge facility. Located on the east side of the City on Shelby Street the facility presently treats the domestic and some industrial wastes from the City of Berlin and accepts septage from surrounding communities.
The wastewater treatment system includes five pumping stations which feed the main pumping station at Watson Street where large solids, rags, sticks, etc., are removed by a automated bar screen and wash press in order to protect the mechanical equipment at the Treatment Plant.
The wastewater then flows through aerated grit chambers in which air is circulated causing organic material to stay in suspension and allowing sand, grit, etc., to settle to the bottom of the chambers for removal.
Degritted wastewater enters the primary clarifiers where settleable solids gradually settle to the bottom. This mass is called primary sludge
Wastewater then goes into aeration tanks in which air is dispersed through a system of fine bubble diffusers, the wastewater is mixed with suspended solids and microorganisms. This process produces an activated sludge which flows into secondary clarifiers where it is allowed th settle. A portion of the settled sludge is recycled to maintain the proper concentration in the aeration tanks and the remainder is mixed with primary sludge in thickening tanks.
In the final step of the process, the treated wastewater flows into tanks where chlorine is added for disinfection before being discharged into the Androscoggin River. The thickened sludge is dewatered with centrifuges and buried at the Mt. Carberry landfill.
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